1. Field of the Invention
The present invention relates generally to toilet flushing systems and particularly to valves for toilets.
2. Description of Prior Art and Related Information
Conventional toilet tanks employ plug and flapper tank valves that are levered open, which remain open while a full tank is emptied. A piston-operated ballcock valve is open whenever the water level in the tank is below a predetermined level. While the ballcock valve is open, part of its total flow is diverted to refill the bowl at the same time the tank is being refilled by the valve.
The piston is driven by a float. The float may be a wrap-around float, which partially wraps around a main step of a water riser that supplies water to the tank through the ballcock valve. A wrap-around float is usually bulky in order to provide sufficient buoyancy for driving the valve piston. Alternatively, a ball-shaped float attached at an end of a long rod may be used as the driving force for the piston, to take advantage of the lever effect provided by the long rod. Thus, a smaller float is needed as compared to the wrap-around float. However, the resting positions of the ball float are relatively distant from the main stem of the valve. Accordingly, conventional ballcock valves are packaged with the rod and the float unassembled, as the rod and the float take too much space and are susceptible to damages if packaged and transported fully assembled. In addition, it is a rather complex operation to adjust the predetermined water level with conventional valve systems.